Radio-frequency identification (RFID) uses radio frequency waves to identify specially tagged items. An RFID system includes two basic components, the RFID tag and the tag reader and/or writer. RFID readers generate an electromagnetic field that interacts with RFID tags to read data stored within RFID tags. RFID writers generate an electromagnetic field that interacts with RFID tags to write data to RFID tags. The RFID tags contain an antenna and microchips encoded with data. RFID tags may be passive, semi-active, or fully active devices. A passive tag can be read up to 10 feet from the reader. The tag then transmits its information via radio waves to the reader, which receives the unique data from the tag. Semi-passive tags, which have a longer range than passive tags, use a battery to power their own circuitry but still draw on a reader field to power their broadcasting. Active tags use battery power to overcome limitations of more passive tags and have a much longer read and write range.